The first close-up of the "flip-flop" phenomenon in a single star*
Astronomy Division, PO Box 3000, 90014 University of Oulu, Finland
2 Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
Corresponding author: H. Korhonen, email@example.com
Accepted: 1 October 2001
We present temperature maps of the active late-type giant FK Com which exhibit the first imagining record of the "flip-flop" phenomenon in a single star. The phenomenon, in which the main part of the spot activity shifts 180°in longitude, discovered a decade ago in FK Com, was reported later also in a number of RS CVn binaries and a single young dwarf. With the surface images obtained right before and after the "flip-flop" , we clearly show that the "flip-flop" phenomenon in FK Com is caused by changing the relative strengths of the spot groups at the two active longitudes, with no actual spot movements across the stellar surface, i.e. exactly as it happens in other active stars.
Key words: stars: activity / stars: individual: FK Com / stars: late-type / starspots
© ESO, 2001